How to Have Firefox Check for Phishing and Dangerous Downloads

by | Dec 17, 2019 | Useful Tech

Want to browse and download with confidence? Find out here how to take a step in that direction and have Mozilla Firefox check for phishing and dangerous downloads automatically.

First, an Engineer Watches Football Furiously

When Everton F.C. played Accrington F.C. on Thursday, October 24, 1889, John Alexander Brodie was in the stands. The match ended 2 – 2, and Brodie was furious.

The beloved Everton were denied a clear goal—and an important victory. The engineer Brodie set to work, and you can see his invention (if barely) all over the world’s stadiums and pitches today.

To prevent spectators from reaching into the field and acting as goalkeepers, and to make goals easier to identify, John Alexander Brodie employed a net around the back of the goal.

Speaking of nets, how about a safety net around Mozilla Firefox that prevents dangerous sites and downloads from reaching into your computer and screen?

How to Have Firefox Check for Phishing and Dangerous Downloads Automatically

To browse with added confidence in Mozilla Firefox, protected by automatic checks for phishing and malware for each page you visit:

  1. Click the hamburger menu button in Mozilla Firefox.

  2. Select Options or Preferences from the menu that has appeared.

    Keyboard shortcut: On macOS, you can also press Command ,
    to open Mozilla Firefox settings.

  3. Open the Privacy & Security category.

  4. Make sure to check Block dangerous and deceptive content under Security.

    Recommended: Typically, do check Block dangerous downloads and Warn you about unwanted and uncommon software as well.
    Not recommended: To disable all safe browsing checks in Mozilla Firefox, uncheck block dangerous and deceptive content.

  5. Close the Options or Preferences browser tab.

How to Have Firefox Check for Phishing and Dangerous Downloads Automatically: FAQ

How does Mozilla Firefox check for dangerous content?

Mozilla Firefox uses Google Safe Browsing to identify potentially unsafe pages and downloads.

For this, Mozilla Firefox downloads a list of dangerous sites from Google Safe Browsing periodically. Then, it checks every page you visit against that list.

If a page is on the list, Mozilla Firefox sends a part of the URL that identifies it uniquely to Google Safe Browsing servers to verify the page is currently on the master list.

For suspicious downloaded files, Mozilla Firefox will send some information about the file to Google Safe Browsing to verify its safety with the service.

I have enabled dangerous content checks; how can I test they are working correctly?

To test Mozilla Firefox’s safe browsing checks are in effect, you can visit the

Can I still visit a site identified as unsafe by Mozilla Firefox?


To override the safe browsing warning and open a suspicious page in Mozilla Firefox:

  1. Click See details on the Deceptive page ahead warning page.
  2. Now click ignore the risk and open the unsafe page.
    Important: Only do this if you have good reason to believe the page you are about to visit will not be immediately dangerous. Do act with caution on the page.

(How to Have Firefox Check for Phishing and Dangerous Downloads Automatically tested with Mozilla Firefox 61–71; updated December 2019)